Arctides regalis Holthuis, 1963

Holthuis, Lipke B., 2006, Revision of the genus Arctides Holthuis, 1960 (Crustacea, Decapoda, Scyllaridae), Zoosystema 28 (2), pp. 417-433 : 424-430

Arctides regalis Holthuis, 1963

( Fig. 2B )

Scyllarus martensii – Edmondson 1933: 223 (p.p.); 1946: 258 (p.p.). — Matthews 1954: 205, figs 1, 2b, 3b, 5b. Non Eduarctus martensii (Pfeffer, 1881) .

Arctides regalis Holthuis, 1963: 58 ; 1991: 177, figs 326b, 331, 332. — Tinker 1965: 46, pl. 11. — Johnson 1971: 98, figs 88-92. — A. Michel 1971: 472. — Burukovsky 1974:102; 1983: 144. — C. Michel 1974:256. — Monod 1975: 1008, fig. 4. — Laboute & Magnier 1978: 42, 115, col. fig. 120; 1979: 42, 115, col. fig. 120. — Phillips et al. 1980: 71. — Ingle 1982: 456, col. fig. — Friese 1984: 6, col. cover fig. — Sekiguchi 1986: 1290; 1987: 331; 1988b: 346, 348. — Lau 1987: 381. — Fielding & Robinson 1987: 32, col. fig. — Phillips & McWilliam 1989: 353, 357, 358. — Baensch & Debelius 1992: 574, col. fig. — Scott 1993: 61, col. fig. — Colin & Arneson 1995: 224, 225, col. fig. 1068. — Gosliner et al. 1996: 221, col. fig. — Polz 1996: 44. — Poupin 1996: 10, 76, 77. — Richer de Forges & Laboute 1996: 64, col. pl. 4a. — Chan 1998: 1041, fig. — Hoover 1998: 201, 244, 245, col. figs. — Nomura 1998: 114, fig. 2. — Debelius 1999a, b, 2000: 225, 3 col. figs. — Retamal 2000: 45, col. fig. 1. — Coutures 2001: 749, fig. 4. — Sekiguchi & Inoue 2002: 749. — Laboute & Richer de Forges 2004: 387, 2 col. figs.

? Arctides antipodarum – A. Michel 1971: 467, 471, 472 (larvae).

Regal Slipper Lobster – DeLuca & DeLuca 1976: 48, fig. — Rosenberg 1988: 105, col. fig.

Archides regalis – Johnson 1979: 327, col. fig.

Arctides sp. – Debelius 1983: 52, 53, col. fig.

Arctides antipodarum – Coleman 1991: 10, col. fig. Non Arctides antipodarum Holthuis, 1960 .

VERNACULAR NAMES. — Regal Slipper Lobster ( Tinker 1965), King’s Hawaiian Lobster ( Friese 1984), Rotband- Bärenkrebs ( Baensch & Debelius 1992), Royal Spanish Lobster ( Chan 1998), Cigarrón Regio ( Debelius 1999a), Hawaii-Bärenkrebs ( Debelius 2000). The other, likewise mostly artificial, names for the species listed by Tinker (1965), viz. Spanish Lobster, Shovel-nosed Lobster and Ula-papapa, evidently are used in Hawaii to indicate all or most Scyllaridae . Retamal (2000) mentioned that the native name for the species at Easter Island is “Raperape”; this name is also used for the other Scyllaridae of Easter Island. No true vernacular names for the species are known to me.

MATERIAL EXAMINED. — Mauritius. 1 juvenile, dry, cl 15 mm ( MG). — Tombeau Bay, reefs, 5 m, I.1965, C. Michel, 1 ♀ cl 60 mm ( RMNH).

La Réunion (as “ Île Bourbon ”). H. de Saussure, 1 ♀ cl 56 mm ( MG). — Leg. Y. Plessis, 1 juvenile ♀ cl 17 mm ( MNHN).

Maldives. Bought from aquariumshop in Frankfurt, Germany, H. Zetsche leg., 1 ♂ cl 40 mm ( SMF).

New Caledonia. Lagoon near Nouméa, 1983, leg. Y. Magnier, 1 ♀ cl 55 mm ( MNHN). — Lighthouse, Amédée Island, 22°35’S, 166°28’E, 20 m, diving, 1 ♂ cl 41 mm ( MNHN). — Récif Toombo, 22°35’S, 166°29’E, outer slope of reef, 8-15 m, diving at night, 8.VIII.1977, 1 ♂ cl 49 mm ( MNHN).

Hawaiian Islands. Received 1.X.1957, S.W.Tinker, 1 ♀ paratype cl 41 mm ( LACM). — Coconut Island, Kaneohe Bay, Oahu, reefs, IV.1959, L. Zukeran leg., P. Illg don., 1 ♂ cl 48 mm, holotype ( RMNH).

Easter Island. 40 m, seen at night, L. Di Salvo (only colour photograph seen).

RECOGNITION CHARACTERS AND COMPARISON WITH A. GUINEENSIS AND A. ANTIPODARUM Arctides regalis is an Indo-West Pacific species much closer to the Atlantic A. guineensis than to A. antipodarum . In fact it resembles the former species so much that at first I thought them to be conspecific. Differences are as follows: 1) behind the gastric spine in A. regalis there is a longitudinal row of three single spinules, whereas in A. guineensis there are two two-topped spinules; 2) the smooth area along the posterior margin of the carapace reaches in the median area all the way to the marginal groove in A. regalis , whereas in the three specimens of A. guineensis examined there are two or three rows of tubercles in-between; and 3) the denticles on the inner margin of the last antennal segment are somewhat smaller in A. regalis than in A. guineensis .

COLOUR

The colour is shown in numerous published colour photographs of the species. The carapace is dark reddish covered by closely placed short black bristles; red spines, often pale yellowish distally with a small dark tip, protrude here and there through the field of bristles. A bright red colour is visible around the orbit; the teeth and spines there are carmine red with whitish tips. Also the lateral margins are reddish, while a reddish or slightly yellowish colour may be seen in the posteromedian region and in the middle of each half of the posterior margin; sometimes the posterior margin shows a distinct red band. The abdomen shows the same reddish colour, especially along the anterior and posterior margins, and on the pleura, the tips of which, however, are whitish or yellowish with a black extremity. The smooth anterior half of the somites as a rule shows two or three paler spots. The short hairs of the dorsal surface are black, they surround the elevated lobulated figures, which are red. The antennulae are uniformly red. The last three antennal segments are almost black dorsally with a rather wide sharply defined red margin. The black colour is most likely caused by the presence of closely placed very short black bristles. The legs are entirely red with the distal part of the dactylus yellowish, and a yellowish band in the distal part of the propodus; in the other segments the yellowish colour is confined to an (often small) spot just behind the articulation of the segments.

SIZE

The cl of the examined female specimens varies between 41 and 60 mm. The holotype male has cl 48 mm; the cl of the other males varies between 40 and 49 mm. The cl of the juveniles are 15 and 17 mm. Richer de Forges & Laboute (1996: 64) indicate the tl to be 150 to 200 mm; Colin & Arneson (1995) and Gosliner et al. (1996) give the length as 150 mm. Most other records have tl less than 170 mm, or 7 inches. Laboute & Richer de Forges (2004) give tl as 200 mm.

DISTRIBUTION

The species is rather widely distributed throughout the Indo-West Pacific region. The type locality is a reef near Coconut Island, Kaneohe Bay, Oahu, Hawaiian Islands. The other records of the species are from Mauritius (C. Michel 1974; Debelius 1999a, b, 2000), La Réunion ( Monod 1975), the Maldives (present record), Kushimoto, Wakayama Prefecture, Honshu, central Japan, 33°28’N, 135°45’E ( Nomura 1998), New Caledonia ( Laboute & Magnier 1978, 1979), southern part of New Caledonia ( Richer de Forges & Laboute 1996), outer slope of Aboré Reef near Nouméa, New Caledonia ( Coutures 2001), outer SW slope and the reefs of the Lagon Sud, New Caledonia ( Laboute & Richer de Forges 2004), 16 miles E of Johnston Island (larvae, Johnson 1971), the Hawaiian Islands ( Edmondson 1933, 1946; Tinker 1965; DeLuca & DeLuca 1976; Friese 1984; Fielding & Robinson 1987; Colin & Arneson 1995; Debelius 1999a, b, 2000), Palea Point, Oahu ( Hoover 1998), Hanauma Bay, SE Oahu ( Scott 1993), Maui, Hawaiian Islands ( Debelius 1999a, b, 2000), Kona coast, Hawaii, Hawaiian Islands ( Rosenberg 1988), Tuamotu Islands, Central Pacific ( Poupin 1996), and Hotu Marotiri, Easter Island ( Retamal 2000). From Easter Island (more precise locality unknown) I have seen a very good unpublished colour photograph (see Material examined).

HABITAT

Arctides regalis inhabits coral reefs; there are several records of it from outer reefs and more exposed reefs. The examined specimens were taken at depths of 5, 8-15, 22 and 40 m. Tinker (1965) reported it from depths of 150 feet (c. 50 m) or more on the outer edge of reefs. Richer de Forges & Laboute (1996: 64) mention depths of 5 to 15 m for this species. Hoover (1998) reported it from 30 feet (c. 10 m). Colin & Arneson (1995) from 20 m, and Retamal (2000) from 12 m depth. It has been reported from caves in reefs; Rosenberg (1988) took the species from submarine lava tubes. Laboute & Richer de Forges (2004) speak about its “habitat caverneux”, and give the depth as 10- 25 m.

BIOLOGY

Richer de Forges & Laboute (1996) characterize the species as “solitaire et farouche”. However, Gosliner et al. (1996) note it to be “found in caves in groups of up to ten animals”, and Debelius (1999a, b, 2000) provided a picture of a group of about 10 specimens, which he presumed to be “an unusual?mating aggregation”. The species is said to be nocturnal ( Laboute & Magnier 1978, 1979); they “shy away from observers during daytime hours, but fully reveal their splendorous colors under the diver’s light at night” ( Johnson 1979); “a nocturnal scavenger” ( Debelius 1999a). They are reported from caves in the exposed outside of coral reefs, where they often are found living on the sides and ceilings of these caves ( Fielding & Robinson 1987). Rosenberg (1988) reported the species from “among orange tube coral” in lava tubes. According to Scott (1993) they “hunt snails, clams, shrimps, and crabs”. Laboute & Richer de Forges (2004) mention its “timides pérégrinations nocturnes” and its very quick disappearance in the depths of its habitat when disturbed.

DEVELOPMENT

Matthews (1954) dealt with the histology and formation of the spermatophore in this species, which he incorrectly identified as Scyllarus martensii . The juvenile from Mauritius (Geneva Museum) is a postlarval stage in which already some of the dorsal spines of the carapace are visible. The median tooth on the posterior margin of the fifth abdominal somite is sharp and well developed, while also two sharp teeth are present on the coxa of the fifth pereiopod. The tips of the pleura of the fourth and fifth abdominal somites are directed forwards. Coutures (2001) dealt with phyllosoma stage I. Johnson (1971) described and figured phyllosoma larvae of the VIIIth and IXth stages.

REMARKS

Edmondson (1946: 258) reported upon a Hawaiian specimen of “ Scyllarus martensii ” of 4 inches (c. 100 mm) long. It is very probable that his specimen (the exact locality of which is unknown) belongs to the present species, with which in Hawaii it has more often been confused. Edmondson’s remark that the species is not found in water of less than 32 fathoms (c. 58 m) evidently is based on Rathbun’s (1906: 896) Hawaiian records of “ Scyllarus martensii ”, which actually are Eduarctus modestus ( Holthuis, 1960) .

The Hawaiian material identified by Matthews (1954: 205) with Scyllarus martensii , judging by its size, evidently also is Arctides regalis . Tinker (1965: 46) already remarked on the confusion in Hawaii of Scyllarus martensii and the present species.

Tinker (1965) gave a short characterization of the species and an excellent photograph.Gorgeous colour photographs of the species were published by many later authors when it became more easy to take and publish underwater colour photographs.

The name regalis (royal) was given to the species in honour of Mrs Mary Eleanore King of Honolulu, Hawaii, in recognition of her many valuable contributions to the promotion of the study of marine biology.

Arctides antipodarum Holthuis, 1960 ( Fig. 3 )

Scyllarus sculptus – Whitelegge 1899: 155, pl. 29. — Coulon 1918: 18. — McNeill 1925: 327. Non Scyllarus sculptus Latreille, 1818 .

Scyllarides guineensis – Holthuis 1946: 100 (p.p.). Non Arctides guineensis ( Spengler, 1799) .

Arctides antipodarum Holthuis, 1960: 154 ; 1991: 175, figs 325a, 327, 328. — Yaldwyn 1961: 1, 3, figs 1, 2. — Gillett & Yaldwyn 1969: 72, 74, fig. 42. — Healy & Yaldwyn 1970: 58, fig. 28. — A. Michel 1971: 467, 471, 472, fig. 6B. — George & Griffin 1972: 228, 230, fig. — Burukovsky 1974: 102; 1983: 144. — Coleman 1977: 133, col. fig.; 1994: 86, 87, col. fig. — Phillips et al. 1980: 71. — Sekiguchi 1988b: 346; 2000: 262. — Davie 2002: 440. — Poore 2004: 209, fig. 58b.

Arctites antipodum – Doak 1971: 88, 89, 110, col. pl. 42.

? Scyllarides sp. – George & George 1979: 78, pl. 70, col. fig. 7.

Non Arctides antipodarum – Coleman 1991: 104, col. fig. (= A. regalis ).

VERNACULAR NAMES. — Red Flapjack ( Healy & Yaldwyn 1970; Davie 2002), Shovel-nosed Crayfish ( Healy & Yaldwyn 1970), Southern Shovel-nosed Cray ( Doak 1971), Southern Shovelnosed Lobster ( Coleman 1994). The (artificial) FAO name is Rough Spanish Lobster ( Holthuis 1991; Poore 2004).

MATERIAL EXAMINED. — Australia. New South Wales, Port Stephens, don. AM, 1912.11.22.142, 1 ♂ ( BMNH). — Off the coast near Sydney, IV.1955, don. AM, 1 ♀ paratype ( RMNH). — Port Jackson, Sydney, don. AM, 1 ♂ ( MNHN). — Off Malabar, S of Sydney, 80 fathoms (c. 146 m), III.1956, A. A. Racek, 1 ♂ holotype ( RMNH). — La Perouse, Botany Bay, 1 ♂ paratype ( AM).

DESCRIPTION

Rostrum T- or V-shaped, constricted at base. Rostral tooth sharp and small, but not smaller than sharp pregastric or gastric tooth; all three teeth with dark horny tips.Two cardiac teeth placed rather wide apart behind cervical groove, followed posteriorly by two converging rows of tubercles. Middle of each lateral half of carapace with single large spine behind cervical groove. A longitudinal row of spines becoming larger anteriorly, extending over branchial region; anterior spines slightly behind and more laterad to spine behind cervical groove. Inner margin of orbit bears three sharply pointed strong teeth; anterior smallest and placed slightly inward, next strongest, only slightly longer than the third (less slender than in A. guineensis ) and bearing small additional posterior tooth. Posterior margin of orbit with two teeth, inner of these broad and two-topped, inner top being broader than outer. Outer margin of orbit crenulate. Strong pointed tooth placed behind inner margin of orbit; a second, smaller tooth about halfway between it and gastric tooth. Orbit widely open anteriorly; intercalated plate low, partly covered by lobe from inner orbital angle. Outer orbital angle ending in two sharp teeth, the anterior tooth very distinct and larger than posterior.Anterolateral angle of carapace placed next to outer orbital tooth, sharply pointed and directed forward and slightly outward. Four sharply pointed anterolateral teeth between anterolateral angle and distinct cervical incision. Ten or 11 posterolateral teeth, anterior much stronger than the rest. No postcervical incision although larger space between first and second posterolateral teeth could be considered as such. Cervical groove rather distinct. Branchiocardiac and postcervical grooves less clearly indicated. Marginal groove deep and wide. Posterior margin with concavity medially. Upper surface of carapace covered by small squames, and shorter and longer hairs, giving specimens shaggy appearance. Double or triple row of tubercles visible between marginal groove and posterior margin.

First abdominal somite with deep uninterrupted transverse rather wide hairy groove, abruptly narrowed on median 1/4 of length. Anterior margin crenulated. Pleura roughened by scale-like tubercles, that are absent from rest of somite. Following somites smooth anteriorly or provided with inconspicuous squamiform tubercles, posterior margins crenulated. Posterior half of abdominal somites with sculpturation like in A. regalis except for smooth, naked parts relatively much smaller and less sharply defined, and interspaces much wider and filled with hairs and tubercles. Appearance rough (much more than in A. regalis where naked parts occupy relatively larger space and are separated by narrow, hair-filled grooves). Central naked figure on somites narrow, raised (more than in A. regalis ). Pleura of second somite relatively wider and shorter; tip placed behind middle, short and directed more posteriorly (in A. regalis tip elongate and directed more downwards, making pleura more slender). Other pleura less slender in A. antipodarum . Tips of fifth pleura blunt. Teeth on antennular somite straight and parallel, their inner margins touching over larger part of their length. Antennae similar in the two species except that teeth on inner margin of last segment are larger and less numerous in A. antipodarum (8-9) than in A. regalis (12-13). Difference between larger inner and smaller outer teeth more distinct in A. antipodarum than in A. regalis . Fourth segment relatively shorter and wider in A. antipodarum than in A. regalis ; teeth less slender, distal tooth not noticeably longer than next outer tooth in A. antipodarum .

First pereiopods similar to those of A. regalis . Second pereiopods differ, being much less elongate; propodus about three times as long as high. Apart from being less slender, the other legs strongly resemble those of A. regalis .

Sternum different from that of A. regalis in having tubercles better developed and grooves wider, being thereby less flat.

Pleopods of second abdominal somite of male as in A. regalis . Following pleopods with endopods reduced to bud. Abdominal sternites slightly more coarsely denticulate than in A. regalis .

Colour

The colour of preserved specimens is uniformly dark reddish with minute yellowish dots and short lines, which are partly obscured by the dark brown pubescence. This coloration extends over the entire upper surface of the body with the exception of the distal segments of the antennae which are pale reddish brown. The legs are purplish covered with numerous small round whitish dots. No coloured bands could be observed here. The brown pubescence of the entire body gives the animals a dark brown colour. Whitelegge (1899: 162) described the colour as follows: “The ground colour is greyish-yellow, in parts almost obliterated by crimson tints, central area of fifth joints of the outer antennae and the margins of the third joints wholly of this tint; the lateral borders and the posterior margins of the carapace, and pleon also, red. Meral joints of legs with a central transverse crimson band, extremities of legs purple or blue. Membrane of telson and uropods yellow, mottled with purple. Inferior surface of antennae yellow dotted with red. The legs red, dotted with yellow”. Yaldwyn (1961: 4) gave the colour of a dead but not preserved specimen as follows: “A dull, mottled red and yellow, rather obscured by the overall covering of short brown setae associated with the tubercles and sculpturing.Two prominent bright red, dorsolateral patches stood out against the yellow background of the anterior half of the first abdominal segment”.

Size The four examined males of this species have cl 89 to 105 mm, the female paratype has cl 91 mm. Whitelegge’s (1899) adult male had cl 90 mm, Yaldwyn’s (1961) adult female 97 mm.

DISTRIBUTION

The type locality is off Malabar, just S of Sydney, New South Wales, Australia. The species is known from SE Australia and New Zealand. The records in the literature are: Port Stephens, New South Wales, Australia ( Whitelegge 1899); Newcastle, New South Wales ( Whitelegge 1899; Coulon 1918); Port Jackson, Sydney, New South Wales ( Whitelegge 1899); off Malabar, S of Sydney ( Holthuis 1960); off Arid Island near Great Barrier Island, Hauraki Gulf, North Island, New Zealand ( Yaldwyn 1961).

HABITAT Little is known about the habitat of the species. The holotype was taken at a depth of 80 fathoms (c. 146 m), the New Zealand specimen reported upon by Yaldwyn (1961) was found “in approximately 10 to 15 fathoms of clear water”.

BIOLOGY

According to Doak (1971) the females are in berry in October.

REMARKS

This species was first discussed in detail by Whitelegge (1899) as Scyllarus sculptus Latreille, 1818 (= Arctides guineensis ( Spengler, 1799)) . Also Coulon (1918) reported on a specimen of this species. In 1960, Holthuis showed that this species is different from Arctides guineensis (of which Scyllarus sculptus and Scyllarides sculptus bermudensis are synonyms) and erected a new species for it. Yaldwyn (1961) reported the species for the first time from New Zealand and gave a good description and figure of it, at the same time providing a key to the New Zealand Scyllaridae .

Dedication

It is a great pleasure to dedicate the present paper to Dr Patsy A. McLaughlin, as a token of appreciation for the help, cooperation and many discussions in the field of decapod taxonomy, and for many other kindnesses received during the more than 40 years of our aquaintance.

Figures

FIG. 2. — A, Arctides guineensis (Spengler, 1799), Bermuda, T. H. Bean leg., lectotype of Scyllarus sculptus bermudensis Verrill, 1922 (USNM), Mrs P. Hogue del.; B, A. regalis Holthuis, 1963, Hawaii, Mrs P. Hogue del.

FIG. 3. — Arctides antipodarum Holthuis, 1960, off Malabar, S of Sydney, Australia, 146 m, III.1956, leg. et don. A. A. Racek, ♂ holotype. Photo RMNH.